Federal's XM193 is actually manufactured at the Lake City Army Ammunition Plant, where USGI ammo is made. Federal's parent company, Alliant TechSystems (ATK), won the contract to operate Lake City beginning in 2000. During the 90s, Lake City was operated by Winchester/Olin, and before that, by DuPont.
Both Winchester's contract and Federal's contract have allowed them to make extra ammo for civilian/foreign sales at the Lake City plant once their military quota was met. Winchester's Q3131 (not "A") was really Lake City M193, but with Winchester's military headstamp, and in commercial Winchester packaging. Note also that Winchester sold Q3130, which was Lake City M80 (7.62x51mm NATO), and several other military calibers. And, now that ATK has the contract, Federal is selling XM193, which again is really Lake City M193.
But, the question is: will this ammo always be available? My opinion is: don't count on it.
Although it's easy to forget, the US is in a state of war in several countries right now, and many other "hot spots" could flare up at any time, resulting in 100% of Lake City's output going to the war effort (heck; they could require Federal's output be redirected too; it's probably already in the contract).
In addition, a piece of legislation, a treaty, or an Exectutive Order could quickly put a stop to the sales of this ammo. This could happen at anytime, or maybe never. There's no way to know.
But the only SAFE assumption is to assume that it will not always be available. Likely, there will always be .223 ammo available, but having ammo that meets the full military specs (M193 velocities, proper bullet, sealed cases, crimped primers) isn't guarenteed. Many of the countries that we used to get surplus military ammo from have stopped the sales of surplus military ammo, and so what we ARE able to get is new-production .223-spec ammo.
This is why most of my shooting is with commercial .223 ammo, though I shoot M193 sometimes too. Still, I have a bunch of M193 set aside, and will only shoot it when I replace it with newer M193.
-Troy